Note: the second dimension of the array Q
must be at least
max1,N if VECT='V' or 'U' and at least 1 if VECT='N'.

On entry: if VECT='U', Q must contain the matrix formed in a previous stage of the reduction (for example, the reduction of a banded symmetric-definite generalized eigenproblem); otherwise Q need not be set.

9 Example

Here A is symmetric and is treated as a band matrix. The program first calls F08HEF (DSBTRD) to reduce A to tridiagonal form T, and to form the orthogonal matrix Q; the results are then passed to F08JEF (DSTEQR) which computes the eigenvalues and eigenvectors of A.